Visitors are allowed to bring foreign currency to the value of 5000 USD when entering China. Current customs regulations state that "Passengers carrying foreign currencies in cash worth more than US$5,000 and intending to take the currencies out of China in the future shall fill out two declaration forms. After being endorsed by the Customs, one copy of the declaration forms will be returned to the passengers for future use at the time when leaving China." (http://shanghai.customs.gov.cn) Penalties apply for breaking regulations, either by failing to declare excess currency, or failing to take it back out of the country, which is checked when you depart.
We suggest that when you exchange currency you request notes with a face value of 50 RMB (renminbi) or 100 RMB, and also that you ensure that your foreign currency notes are clean and undamaged.
You can use your cash or credit card to withdraw RMB at commercial banks. Charges will depend on the bank or ATM where you withdraw cash, as well as the kind of card you hold. You can also use your card to pay for goods and services at shops, restaurants, supermarkets and hotels, and again charges will depend on your card, and where you are paying. It may be more difficult to use your card in extremely remote areas.
Foreign currency can be exchanged at your hotel, at a bank or through your tour guide. US currency is preferred but other major currencies are also accepted in all major cities.
Normally, apart from dinners (you can pay by card in most of the restaurants), nighttime activities, shopping and optional tips, you will not be paying additional fees. We suggest that you allow 300-500 RMB (60-100 USD) per day.
Renminbi is the word for currency. The cash units are referred to as jiao (small denominations) and yuan. As of 2013, renminbi is available in denominations from ¥0.1, ¥0.2, ¥0.5 (1, 2, and 5 jiao), ¥1, ¥2, ¥3, ¥5, ¥10, ¥20, ¥50, and ¥100 yuan.
We also recommend that you only purchase renminbi from authorized dealers, and retain your receipt, to avoid the risk of being given forged notes.